Summary

A vulnerability in the Multiprotocol Label Switching (MPLS) Label Distribution Protocol (LDP) packet processing feature of Cisco IOS XR could allow an unauthenticated, remote attacker to cause a reload of the MPLS LDP process on the affected device.

The vulnerability is due to improper processing of crafted MPLS LDP packets. An attacker could exploit this vulnerability by sending crafted MPLS LDP packets to be processed by an affected device. An exploit could allow the attacker to cause a reload of the MPLS LDP process on the affected device.

Cisco has confirmed the vulnerability and released software updates.

To exploit this vulnerability, an attacker may need to acquire additional information about the targeted device, such as whether the device is configured to process MPLS LDP packets. A device configured to process MPLS LDP packets is required for a successful exploit.

Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.

Affected Products

Cisco has released bug ID CSCuu77478 for registered users, which contains additional details and an up-to-date list of affected product versions.

Vulnerable Products

At the time this alert was first published, Cisco IOS XR Software Release 5.1.3 was vulnerable. Later releases of Cisco IOS XR Software may also be vulnerable.

Products Confirmed Not Vulnerable

No other Cisco products are currently known to be affected by these vulnerabilities.

Workarounds

Administrators are advised to apply the appropriate updates.

Administrators are advised to allow only trusted users to have network access.

Administrators can help protect affected systems from external attacks by using a solid firewall strategy.

Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.

Administrators are advised to monitor affected systems.

Fixed Software

Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at tac@cisco.com.

Exploitation and Public Announcements

The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

Cisco Security Vulnerability Policy

To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.

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Revision History

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Cisco Security Vulnerability Policy

To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.